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The mkiv Supra Owners Club

Strong petrol smell in oil and smoke from catch tank


marc_p

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Ok, so prior to Dragonball tomorrow, went to change the oil in the car and it STANK of petrol and had seriously thinned itself(probably done about 500 miles since last change).

 

So I dropped the oil and filter and put some new 10w-40 semi in it and let it idle for around 10 minutes, in which time the catch tank is letting out some smoke from the filter, so I take the tanks bung out and drain some fluid from it, it's yellowy in appearance and again stinks of fuel.

 

Took the car out for a brief 5-10 minuite drive, get back and the oil still stinks of fuel when I take the cap off and also the oil around the oil cap was very thin and petrol like in its feel.

 

Note that the car is on a rough but reasonable base map and I haven't been giving it hard acceleration and the AFRs seem reasonable, slightly on the rich side but nothing drastic(13-14 at idle, 12-13 cruising, 10-12 once opened up a bit).

 

Any help appreciated, should I drop the oil once again? Go to thicker oil? Do an engine flush? As the petrol could of been lingering from initial mapping but no way to find out until I get rid of the petrol smell to see if it comes back.

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No, still on the exact same map, it didn't have its final map as there was some higher end issues of the car stuttering, so it had a limiter of 5.5k rpm put on the Motec and safely and conservatively mapped up to this level.

 

What's the likely damage? Bearings gone?

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Oil dilution to the point where the oil stinks of petrol and is watery may well cause ring damage. The oil pump itself may be harmed, and if the engine has seen any ral load the bearings won't like it either. To water the oil with fuel, with no other cause than running rich, must have meant it ran a long time, crazy rich. I wouldn't run it until the mapping is finalized and you are sure it has no other issues. A backfire can blow the cam covers and the sump off and start a serious engine fire. I am surprised it didn't show signs of such mad richness, was it not billowing black smoke?

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Oil dilution to the point where the oil stinks of petrol and is watery may well cause ring damage. The oil pump itself may be harmed, and if the engine has seen any ral load the bearings won't like it either. To water the oil with fuel, with no other cause than running rich, must have meant it ran a long time, crazy rich. I wouldn't run it until the mapping is finalized and you are sure it has no other issues. A backfire can blow the cam covers and the sump off and start a serious engine fire. I am surprised it didn't show signs of such mad richness, was it not billowing black smoke?

 

could it be possible for a fuel injector leaking and fuel running down inlet and if valve is open onto piston then slowly seep past rings? and so why it does not showing running too rich but diluting oil?

it might not showing stating issues if used only once, twice a week? i would thought it would show some symptoms if this was the case.

 

i may be talking out my arse, just another take on the problem.

 

regards chris

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Oil dilution to the point where the oil stinks of petrol and is watery may well cause ring damage. The oil pump itself may be harmed, and if the engine has seen any ral load the bearings won't like it either. To water the oil with fuel, with no other cause than running rich, must have meant it ran a long time, crazy rich. I wouldn't run it until the mapping is finalized and you are sure it has no other issues. A backfire can blow the cam covers and the sump off and start a serious engine fire. I am surprised it didn't show signs of such mad richness, was it not billowing black smoke?

 

There was some black smoke when the turbo started to spoil, but not billowing, just a puff.

 

However, I think it may have crank walk, as although the crank pulley seems fine I think the damper is doing its job because when I took the spark plug cover off, the cam belt is sliding back and forth about 3mm on the cam pulleys and looking from above, the back plate of the crank pulley looks like it may also be moving in and out.

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There was some black smoke when the turbo started to spoil, but not billowing, just a puff.

 

However, I think it may have crank walk, as although the crank pulley seems fine I think the damper is doing its job because when I took the spark plug cover off, the cam belt is sliding back and forth about 3mm on the cam pulleys and looking from above, the back plate of the crank pulley looks like it may also be moving in and out.

 

That would do it :)

 

So potentially rebuild time anyway? If it was me id be ensuring break down cover includes Europe and put a few litres of oil through it and accept it may be going to SRD sooner than planned.

 

Thats all dependent on exactly how much fuel is in the oil due to risk of engine fire as Chris pointed out.

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